As of 1:48 PM CST on December 1, 2025, all 10 cities in Mason County, IL in our database have a UV Index reading of Low. The city with the highest UV Index reading right now is San Jose, IL with a reading of 0.9.
Over the next 24 hours, the highest UV Index reading in Mason County, IL is expected to be 2.1 in San Jose between 12:00 PM - 1:00 PM CST tomorrow.
| Range | 0 - 2 | 3 - 5 | 6 - 7 | 8 - 10 | 11+ |
|---|---|---|---|---|---|
| Color | |||||
| Risk | Low | Moderate | High | Very High | Extreme |